libsrtp: Copy ar-lib from automake

since libsrtp does not run automake, it does not get to add missing
files e.g. ar-lib macro file which is needed during autoreconf,
therefore copy this file from native automake to use here

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Cc: Andreas Müller <schnitzeltony@gmail.com>

meta-multimedia/recipes-support/libsrtp/libsrtp_2.3.0.bb

@@ -12,6 +12,9 @@ SRC_URI = "git://github.com/cisco/libsrtp.git"
 inherit autotools pkgconfig
 
 EXTRA_OEMAKE += "shared_library"
-EXTRA_AUTORECONF += "--exclude=automake"
+
+do_configure_prepend() {
+    cp ${STAGING_DATADIR_NATIVE}/automake-*/ar-lib ${S}
+}
 
 ALLOW_EMPTY_${PN} = "1"